Features: brand new and high quality With BOOT and RESET buttons reserved, users can update the firmware via DFU mode by USB. Added for protection circuit on the thermistor avoids burning the main control chip caused by leakage current from the heating rod. User can select the thermistor's pull-up resistors values through jumper wire, so as to support PT1000 (2.2K pull-up resistors), which makes it convenient for DIY. Connect the USB witha jumper cap to get it power on, which effectively isolates the main control board DC-DC from USB 5V. Reserved I2C interface allows for filament broke and clogged detection, and supports other DIY functions. Added anti-flyback diodes on the heating rod and fans' ports effectively protect the MOS tube from being burned due to reverse voltage. Anti-reverse connection for protection on the power interface prevents users from burning the motherboard when mistakenly connecting the reverse power line during DIY. Specifications: External Size : 40x 40mm Installation Size: spacing 31x 31mm, M3 screw holex 4 Microprocessor: ARM Cortex-M0 STM32F072C8T6 48MHz Input Voltage: DC12V-DC24V 9A Logic Voltage: for DC 3.3V Heating Interface: Heating Rod (E0), max. output current: 5A Onboard Sensor: ADXL345 Fan Interfaces: Two CNC Fans (FAN0, FAN1) Maximum Output Current of Fan Interface: 1A, for peak value 1.5A Expansion Interfaces: EndStop, I2C, Probe, RGB, PT100/PT1000, USB , CAN Interface Motor Drive: Onboard TMC2209 Driver Working Mode: UART Stepper Motor Interface: EM Temperature Sensor Interface(Optional): 1 channel 100K NTC or PT1000 (TH0), 1 channel PT100/PT1000 USB Communication Interface: USB-Type-C for DC 5V Max. Output Current: 1A Package Includes: 1PC x EBB42 Board note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!